handle thermocouples, platinum resistance temperature detectors (RTDs), and analog inputs. Functionality includes auto-tuning (AT) that can help implement proportional-integral-digital (PID) control. Self-tuning can be used to determine the PID constants using the step response method manually. Up to 16 temperature controllers can be connected using a single DeviceNet communication hub. Thermo management software EJ1N temperature controllers can benefit from using the EST2-2C- MV4 thermo support software package. This software enables editing and batch downloading parameters from a personal computer, speeding configuration and commissioning. It also supports trend monitoring from up to 31 controllers. Parameters that can be monitored include process values (PVs), system values (SVs), manipulated values (MVs), PID parameters, and alarm on/off status. Supported logic operations include setting inputs from external inputs (event inputs) or temperature status, sending values to external control or auxiliary outputs, and changing the operating state with on/off delays.
Implementing phase control and optimum cycle control
Omron offers designers several options for implementing on/ off control, phase control, or optimum cycle control, including the model G3PW-A245EU-S, that’s rated for operating voltages from 100 V AC to 240 V AC ; other models are available for operation from 400 V AC to 480 V AC . These controllers include heater burnout detection for increased system uptime. An RS-485 communication port is used to set variables and monitor load current. The G3PW controllers support total runtime monitoring and are suited for use with constant resistance and variable resistance loads.
Figure 2: G3ZA multi-channel power controllers support three-phase optimum cycle control. (Image source: Omron)
Three-phase optimum cycle control has been added for
three-phase heaters. The model G3ZA-4H203-FLK-UTU is rated for operation from 100 V AC to 240 V AC and includes RS-484 connectivity. Other models are available for operation from 400 V AC to 480 V AC . Temperature controllers for system integration Temperature controllers like the EJ1N-TC4A-QQ can connect to power controllers like the G3ZA series of multi-channel controllers. They have inputs for temperature sensors as well as connections for the system PLC. The input unit can
Multi-channel power controllers
The G3ZA multi-channel power controller series adds three- phase optimum cycle control to support three-phase heaters. When used with zero-cross SSRs, it supports low-noise power operation. One controller can control up to 8 SSRs. In addition, a soft-start function is available for lamp heaters (Figure 2).
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